1. Field of the Invention
The present invention relates to a method and apparatus for recording and reproducing a video signal, more particularly to a method and apparatus which enables a reduction in noise and power consumption.
2. Description of the Related Art
There is a strong demand for reducing the noise in camcorders and other combination video cameras and recorders.
A Japanese Laid-Open Patent Application No. 62-186681 discloses a method enabling long recording by reducing tape running speed of a magnetic tape to 1/n, reducing rotational speed of a rotary drum to 1/n, and recording the video signal by time expansion, that is, intermittently.
According to this method, noise is reduced since the rotational speed of the rotary drum becomes lower. Further, there is an advantage that the reduction of the rotational speed of the rotary drum and the reduction tape running speed of the magnetic tape enable the power consumed by the drive system for driving the same to be reduced.
While the noise was reduced, however, there was the problem of a reduction in the quality of the recorded video signal due to the intermittent recording.
Japanese Laid-Open Patent Application No. 63-160479 discloses a method enabling effective recording of a video signal with a broad frequency band, that is, the improvement of the recording density, by dividing the video signal during the horizontal scanning into 1/N, performing time expansion by a factor of N on the thus divided video signal, and successively recording on the magnetic tape the (N+1) system FM modulated signal through (N+1) number of equidistantly arranged magnetic heads. The rotational speed of the rotary drum is not changed.
There was a problem, however, that the noise could not be reduced since the rotational speed of the rotary drum was left unchanged.
Japanese Laid-Open Patent Aapplication No. 1-49386 discloses a method enabling a rotary drum to be made smaller and the rotational speed not increased that much by arranging k number, at least three, for example, four, magnetic heads at equal intervals of 90 degrees around the rotary drum. This enables parallel recording on m (m being 2 or more or k-1) number of tracks by m number of heads among these, for example, three magnetic heads. When forming a video signal in the horizontal direction by n number of tracks, recording one unit of video signal by time expansion by a factor of [(n+m-1}/n], for example, when n=2 and m=3, by a factor of 2. In this example, there are four magnetic heads and the wrap angle is 270 degrees. When the diameter of the rotary drum is reduced to 2/3, the rotational speed of the rotary drum is increased to 3/2.
Since the rotational speed of the rotary drum is increased to 3/2, there is the problem that the noise becomes that much greater.
Japanese Patent Publication No. 5-50068 discloses provision of four magnetic heads at equal intervals about a rotary drum, that is, at 90 degree intervals, winding the magnetic tape around the rotary drum at a wrap angle of 180 degrees, and recording the video signal by time expansion. Note that in this technique, the rotational speed of the rotary drum is not changed.
Since the rotational speed of the rotary drum remains unchanged, the noise cannot be lowered. Further, since four recording magnetic heads are disposed at equal intervals, i.e., at 90 degree intervals, when four reproducing magnetic heads are disposed between these recording magnetic heads, there is crosstalk between the recording magnetic heads and reproducing magnetic heads.